1. Field of the Invention
A brushless direct current motor, a compressor and an air conditioner having the same consistent with the present general inventive concept relate to improving a configuration preventing an overload of a brushless direct current motor.
2. Description of the Related Art
In general, an air conditioner acting as a heat pump operates in a heating mode and a cooling mode according to a demand of a user. For example, the heat pump heats a room in the heating mode in winter, and cools the room in the cooling mode in summer. Also, the heat pump may adjust the humidity of the room, and clean the air of the room.
In general, the heat pump includes an indoor unit including an indoor heat exchanger to heat or cool a room and an indoor fan, and an outdoor unit including an outdoor heat exchanger, an outdoor fan and a compressor.
During a heating cycle in the heating mode, at first, the compressor compresses a refrigerant. The compressed refrigerant is supplied to the indoor heat exchanger, and air which is heated by the indoor heat exchanger is discharged into the room, thereby heating the room.
In a cooling cycle of the cooling mode, at first, the compressor compresses the refrigerant. The compressed refrigerant is supplied to the outdoor heat exchanger and evaporated in the indoor heat exchanger, and air which is cooled by the indoor heat exchanger is discharged into the room, thereby cooling the room. The refrigerant subject to the heat-exchange operation in the indoor unit is supplied to the outdoor heat exchanger.
In the cooling and heating processes, the compressor repeats a compressing process of the refrigerant. The air conditioner successively performs compression, condensation, expansion and evaporation processes.
In general, a compressor includes a driving shaft rotated by a magnetic flux variation of a brushless direct current motor provided with a stator and a rotor having a permanent magnet, and a rolling piston coupled to an eccentric part of the driving shaft to rotate in an inner space of a cylinder as the driving shaft rotates.
Also, the compressor includes a control part to control an operation of the brushless direct current motor based on various sensors to achieve a stable and safe operation. The sensors may sense the position of the rotor, or include a thermostat which senses temperature. However, the brushless direct current motor may be required to be used under poor environmental conditions, which may be problematic for the sensors.
Accordingly, if the stator is provided with a temperature sensor and the brushless direct current motor is used under poor environmental conditions, the temperature of the environment in which the brushless direct current motor is used may improperly influence the temperature sensor.